\begin{tabular}{l*{4}{c}}
\toprule
            &Pre(2005--09)&Post(2010--15)&Post(2010--15)&Post(2010--15)\\
\midrule
High        &        22.9&        23.3&        23.3&        23.3\\
Low         &        19.4&        17.7&         6.2&        23.2\\
N           &       137.0&       207.0&        78.0&       129.0\\
\bottomrule
\end{tabular}
